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Diffstat (limited to 'JavaScriptCore/wtf/DecimalNumber.cpp')
| -rw-r--r-- | JavaScriptCore/wtf/DecimalNumber.cpp | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/JavaScriptCore/wtf/DecimalNumber.cpp b/JavaScriptCore/wtf/DecimalNumber.cpp new file mode 100644 index 0000000..70304e2 --- /dev/null +++ b/JavaScriptCore/wtf/DecimalNumber.cpp @@ -0,0 +1,199 @@ +/* + * Copyright (C) 2010 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" +#include "DecimalNumber.h" +#include <math.h> +#include <wtf/MathExtras.h> +#include <wtf/text/WTFString.h> + +namespace WTF { + +unsigned DecimalNumber::bufferLengthForStringDecimal() const +{ + unsigned length = 0; + // if the exponent is negative the number decimal representation is of the form: + // [<sign>]0.[<zeros>]<significand> + if (m_exponent < 0) { + if (m_sign) + ++length; + length += 2; // for "0." + length += -m_exponent - 1; + length += m_precision; + return length; + } + + unsigned digitsBeforeDecimalPoint = m_exponent + 1; + + // If the precision is <= than the number of digits to get up to the decimal + // point, then there is no fractional part, number is of the form: + // [<sign>]<significand>[<zeros>] + if (m_precision <= digitsBeforeDecimalPoint) { + if (m_sign) + ++length; + length += m_precision; + length += digitsBeforeDecimalPoint - m_precision; + return length; + } + + // If we get here, number starts before the decimal point, and ends after it, + // as such is of the form: + // [<sign>]<significand-begin>.<significand-end> + if (m_sign) + ++length; + length += digitsBeforeDecimalPoint; + ++length; // for decimal point + length += m_precision - digitsBeforeDecimalPoint; + + return length; +} + +unsigned DecimalNumber::bufferLengthForStringExponential() const +{ + unsigned length = 0; + if (m_sign) + ++length; + + // Add the significand + ++length; + + if (m_precision > 1) { + ++length; // for decimal point + length += m_precision - 1; + } + + // Add "e+" or "e-" + length += 2; + + int exponent = (m_exponent >= 0) ? m_exponent : -m_exponent; + + // Add the exponent + if (exponent >= 100) + ++length; + if (exponent >= 10) + ++length; + ++length; + + return length; +} + +unsigned DecimalNumber::toStringDecimal(UChar* buffer, unsigned bufferLength) const +{ + ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringDecimal()); + + // Should always be at least one digit to add to the string! + ASSERT(m_precision); + UChar* next = buffer; + + // if the exponent is negative the number decimal representation is of the form: + // [<sign>]0.[<zeros>]<significand> + if (m_exponent < 0) { + unsigned zeros = -m_exponent - 1; + + if (m_sign) + *next++ = '-'; + *next++ = '0'; + *next++ = '.'; + for (unsigned i = 0; i < zeros; ++i) + *next++ = '0'; + for (unsigned i = 0; i < m_precision; ++i) + *next++ = m_significand[i]; + + return next - buffer; + } + + unsigned digitsBeforeDecimalPoint = m_exponent + 1; + + // If the precision is <= than the number of digits to get up to the decimal + // point, then there is no fractional part, number is of the form: + // [<sign>]<significand>[<zeros>] + if (m_precision <= digitsBeforeDecimalPoint) { + if (m_sign) + *next++ = '-'; + for (unsigned i = 0; i < m_precision; ++i) + *next++ = m_significand[i]; + for (unsigned i = 0; i < (digitsBeforeDecimalPoint - m_precision); ++i) + *next++ = '0'; + + return next - buffer; + } + + // If we get here, number starts before the decimal point, and ends after it, + // as such is of the form: + // [<sign>]<significand-begin>.<significand-end> + + if (m_sign) + *next++ = '-'; + for (unsigned i = 0; i < digitsBeforeDecimalPoint; ++i) + *next++ = m_significand[i]; + *next++ = '.'; + for (unsigned i = digitsBeforeDecimalPoint; i < m_precision; ++i) + *next++ = m_significand[i]; + + return next - buffer; +} + +unsigned DecimalNumber::toStringExponential(UChar* buffer, unsigned bufferLength) const +{ + ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringExponential()); + + // Should always be at least one digit to add to the string! + ASSERT(m_precision); + UChar* next = buffer; + + // Add the sign + if (m_sign) + *next++ = '-'; + + // Add the significand + *next++ = m_significand[0]; + if (m_precision > 1) { + *next++ = '.'; + for (unsigned i = 1; i < m_precision; ++i) + *next++ = m_significand[i]; + } + + // Add "e+" or "e-" + *next++ = 'e'; + int exponent; + if (m_exponent >= 0) { + *next++ = '+'; + exponent = m_exponent; + } else { + *next++ = '-'; + exponent = -m_exponent; + } + + // Add the exponent + if (exponent >= 100) + *next++ = '0' + exponent / 100; + if (exponent >= 10) + *next++ = '0' + (exponent % 100) / 10; + *next++ = '0' + exponent % 10; + + return next - buffer; +} + +} // namespace WTF |